CNET Editors' Rating

The Bottom LineSony's taken a risk with the Alpha SLT-A55 camera, but it's paid off. The A55's innovative translucent-mirror technology makes for a blisteringly quick snapper that delivers excellent results.

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Don't be fooled by your first glimpse of Sony's Alpha SLT-A55 and SLT-A33 cameras -- they may look like traditional digital SLRs but, underneath the bonnet, they pack an interesting new approach. We took both cameras out for a spin, and this review of the A55 highlights the difference between it and the Sony Alpha SLT-A33.

Although they sit in the middle of Sony's dSLR range, competition comes in the form of hybrid cameras like the Panasonic Lumix DMC-G2. Both the A55 and A33 come with an 18-55 mm kit lens. According to Sony, the A33 kit will cost between £600 and £700 when it's released in early September. The A55 will cost between £700 and £800 when let loose in early October.

Rapid-fire snappers

The A55 is a 16.2-megapixel model, while the A33 packs 14.2-megapixels. The A33 uses the same sensor as the Sony NEX-5 and NEX-3, the first cameras in Sony's NEX interchangeable-lens compact range, while the A55 uses a larger APS-C CMOS sensor. With their innovative translucent-mirror technology, the A55 and A33 blur the lines between traditional dSLRs and newer interchangeable-lens cameras.

Although they look, feel and handle like dSLRs, technically these cameras aren't: they have a mirror inside, but the mirror doesn't move, so they don't have the single-lens reflex action that gives SLRs their name. The mirror is semi-transparent -- also known as a pellicle mirror -- and lets 70 per cent of the light through to the main sensor, while the rest is bounced up to a phase-detection autofocus sensor.

This means you get continuous autofocus, both when snapping moving subjects and shooting video. In practice, the full-time autofocus and lack of moving parts mean the cameras are blisteringly fast: the A55 captures up to 10 frames per second, while the A33 fires off 7fps.

The high-speed shooting modes don't allow you to adjust exposure, but dropping the frame rate to a still creditable 6fps means you can take charge of the settings.

Small wonder

The fixed mirror means the cameras are relatively small -- 23 per cent smaller and 26 per cent lighter than the Sony Alpha DSLR-A550, to be precise. They're very light, but with a solid and comfortable rubberised grip.

The lack of a moving mirror also means that the viewfinder is electronic, rather than optical. The advantage of an EVF is that you can preview your settings, and see 100 per cent of the frame. Sony's 'Tru-Finder' EVF also offers on-screen whistles and bells, including focus-point magnification, a histogram, and a digital spirit level. The 1,440,000-dot EVF is bright and clear, and the on-screen display looks like a video game, which we admit we found pretty cool.

The rotating screen will let you hold the camera at all manner of crazy angles and still seeing what you're doing.

Moving the camera away from your eye automatically switches between the EVF and live view on the screen. The cameras' fold-out screens have a new design, with a fully articulated pivot meaning you can see the 76mm (3-inch), 16:9 LCD from either side, as well as straight up and down. It's super-handy for shooting with the camera held up high or down low.

Rich Trenholm is a senior editor at CNET where he covers everything from phones to bionic implants. Based in London since 2007, he has travelled the world seeking out the latest and best consumer technology for your enjoyment.
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